The use of an ion beam column for repairing semiconductor masks is known from the prior art. The ion beam column has an ion source, which provides a plurality of ions of different suitable elements, which have different ion masses. The ions are combined in an ion beam and directed toward a semiconductor mask to be repaired. A desired type of ions is selected on the basis of their mass with the help of a filter which provides both an electric field and a magnetic field. Ultimately only these selected ions are focused on the semiconductor mask as an ion beam. Due to an interaction of the ion beam incident on the semiconductor mask with the material of the semiconductor mask, interaction particles are generated, in particular secondary electrons or secondary ions, which are emitted from the semiconductor mask. A detector detects the interaction particles. Reference is made to U.S. Pat. No. 5,035,787 and WO 88/09049 regarding the above prior art, which are both incorporated herein by reference.
As mentioned previously, the known method relates to the repair of semiconductor masks only, however, not to an analysis of a sample.
For analyzing a crystalline structure of a sample it is known from the prior art to determine the distribution of electrons, which are backscattered from the sample after an electron beam has hit a sample. The above method is known by the designation EBSD (Electron Backscattered Diffraction). The use of the above method in a particle beam device which provides both an ion beam and an electron beam is known. A sample to be analyzed is initially prepared with the aid of the ion beam. Subsequently an electron beam is focused onto the sample. Due to the interaction between the electrons of the electron beam and the material of the sample, electrons are backscattered from the surface of the sample. The distribution of the backscattered electrons is determined to thereby obtain information about the crystalline structure of the sample. A two-dimensional detector in the form of a CCD camera may be used for determining the distribution of the backscattered electrons.
For samples containing low-density materials, which are examined in the above-mentioned particle beam device, however, no meaningful measurements are obtainable. The use of images of the spatial distribution of the backscattered electrons, generated by the EBSD method, provides no clear information about the crystalline structure of the above-mentioned sample. The conclusion has been drawn that this is probably due to the type of preparation of the sample. Gallium ions, which penetrate the sample and destroy the crystalline structure of the sample, are normally used for preparing the sample.
Accordingly, it would be desirable to provide a device and method for analyzing a sample with the help of which clear conclusions may be drawn about the crystalline structure even for samples composed of low-density materials.